1. The Field of the Invention
The present invention relates to medical devices usable to repair a fistula. More particularly, the present invention relates to medical devices having distal flexibility and/or controllability to repair a fistula.
2. The Related Technology
In medicine, a fistula is an abnormal connection or passageway between two organs or vessels that normally do not connect. Usually, a fistula is an abnormal passageway between two such organs or vessels, where a first body lumen thereby is abnormally connected to a second body lumen (e.g., organ to organ, organ to vessel, and/or vessel to vessel). The fistula itself is often not well defined and can be represented as a tear, opening, or hole in the tissue so as to have two different openings.
Fistulas can be malformations within the body with serious health consequences, and may even lead to death. Often, the body fluid contained in one body organ or lumen can pass through the fistula to another body organ or lumen. Such passage of body fluids can contaminate or cross-contaminate the body lumens when the fluids should not be passed therebetween. Also, a fistula in a vessel can lead to unfavorable blood deposits in an adjacent lumen or organ.
Some fistulas can be caused by disease. For example, inflammatory bowel diseases, such as Crohn's disease and ulcerative colitis, are the leading causes of anorectal, enteroenteral, and enterocutaneous fistulas. A person with severe stage-3 hidradenitis suppurativa may also develop fistulas.
Some fistulas can be an unfortunate consequence of a medical procedure, where the fistula forms during the implementation of the medical procedure. For example, complications from gallbladder surgery can lead to a biliary fistula. Also, radiation therapy can lead to a vesicovaginal fistula. However, an intentional arteriovenous fistula can be deliberately created in some instances as part of a therapy.
Some fistulas can be caused by trauma. For example, head trauma can lead to perilymph fistulas, whereas trauma to other parts of the body can cause unwanted arteriovenous fistulas. Obstructed labor can lead to vesicovaginal and rectovaginal fistulas. An obstetric fistula develops when blood supply to the tissues of the vagina and the bladder and/or rectum is cut off during prolonged obstructed labor. At some point, the tissues can die and a hole forms in the tissue through which urine and/or feces pass uncontrollably. Vesicovaginal and rectovaginal fistulas may also be caused by trauma.
Fistulas need to be repaired because they are painful and can cause secondary ailments from certain body fluids or other substances passing into a conduit, lumen, or other body cavity or tissue in which the body fluid does not belong. This can include urine passing into the vaginal or colon conduits, food or drink passing into the lungs, and blood passing from a vessel into another type of body conduit, such as an airway. Currently, fistulas are difficult to fix and require invasive surgery where the fistula is manually stitched closed. Often, surgeries that fix fistulas actually require forming an incision in a patient larger than the actual fistula itself, which is problematic because the incision also has to heal and is susceptible to infection from the surrounding environment and from the fistula itself.
Surgery is often required to ensure adequate drainage of the fistula so that pus may escape without forming an abscess. Various surgical procedures are commonly used to close a fistula, and utilize a common suture to stitch the fistula closed. For example, a fistulotomy can include placement of a seton, which is a cord that is passed through the path of the fistula to keep it open for draining. Also, an endorectal flap procedure can be performed where healthy tissue is pulled over the internal side of the fistula to keep feces or other material from reinfecting the channel. Additionally, treatments can include filling the fistula with fibrin glue, or plugging it with plugs made of porcine small intestine submucosa or other biocompatible substance. Surgery for anorectal fistulae is not without side effects, including recurrence, reinfection, and incontinence. The limited space available during the surgical procedure complicates the ability to properly stitch the fistula closed.